Samish Bay is closed to the recreational harvesting of shellfish and the commercial harvesting of geoduck clams because of the presence of a toxin-producing algae.
The toxin can cause paralytic shellfish poisoning in those who consume affected mussels, oysters or clams.
Paralytic shellfish poisoning affects the central nervous system and paralyzes muscles, which can cause an upset stomach, dizziness, numbness and difficulty breathing, and in some cases may be fatal, according to the state Department of Health.
The commercial harvesting of geoducks was closed Tuesday by the state Department of Health after samples of the clams collected Sunday from Samish Bay showed concentrations of the toxin associated with the algae in concentrations above the state’s precautionary threshold.
Samples of other clam and oyster species commercially grown in the bay had lower levels of the toxin, Department of Health marine biotoxin lead Jerry Borchert said.
Recreational harvesting was closed as a precaution because of the possibility of “hot spots” for the toxin throughout the bay.
“At this point just to be safe, especially with the low tides we had this week, we’re going to keep it closed,” he said. “Conditions can change rapidly this time of year.”
The Department of Health is now collecting shellfish samples from the bay more frequently to monitor changes in the levels of the toxin.
“We’re going to continue to test a lot of shellfish and keep a real close eye on it,” Borchert said.
The biotoxin caused shellfish harvest closures in Samish Bay in September and October of last year. Before that, its presence last led to harvest closures in July 2010.
Similar to during 2018, the toxin was first detected in waters to the north, in Whatcom County, Borchert said. As of now, Samish Bay is the only area known to be affected in Skagit County.